Kinetics and Adsorption Ions of Heavy Metal by Modified Alumino-Silicates

Adsorption isotherms of Ni (II) and Cu (II) ions by alumino-silicates, modified with N, N'-bis (3-triethoxysilylpropyl) thiocarbamide (BTM-3), and HCl, were obtained. The adsorption kinetics of heavy metal ions is studied, using the kinetic pseudo-first and pseudo-second order models. It is shown that, when alumino-silicates are modified, the rate and energy of adsorption increase. It is established that the kinetics of the adsorption of the studied ions is best described by a pseudo-second order model. The maximum value of the adsorption rate constant of 33.7∙10-5 g/ (mmol min) corresponds to nickel (II) ions for alumino-silicates, modified with HCl. The maximum value of the adsorption rate constant value of 2.91∙10-5 g/ (mmol min) for alumino-silicates, modified with BTM-3, corresponds to Cu (II) ions.

EFFECT OF DIATOMEAOUS EARTH TREATMENT USING HYDROGEN CHLORIDE AND SULFURIC ACID ON KINETICS OF CADMIUM(II) ADSORPTION

In this research, treatment of diatomaceous earth, Sangiran, Central Java using hydrogen chloride (HCl) and sulfuric acid (H2SO4) on kinetics of Cd(II) adsorption in aqueous solution has been carried out. The work was conducted by mixing an amount of grounded diatomaceous earth (200 mesh in size) with HCl or H2SO4 solution in various concentrations for two hours at temperature range of 100 - 150oC. The mixture was then filtered and washed with water until the filtrate pH is approximately 7 and then the residue was dried for four hours at a temperature of 70oC. The product was used as an adsorbent to adsorb Cd(II) in aqueous solution with various concentrations. The Cd(II) adsorbed was determined by analyzing the rest of Cd(II) in the solution using atomic absorption spectrophotometry. The effect of treatment was evaluated from kinetic parameter of adsorption rate constant calculated based on the simple kinetic model. Results showed that before equilibrium condition reached, adsorpstion of Cd(II) occurred through two steps, i.e. a step tends to follow a reaction of irreversible first order (step I) followed by reaction of reversible first order (step II). Treatment with acids, either hydrogen chloride or sulfuric acid, decreased adsorption rate constant for the step I from 15.2/min to a range of 6.4 - 9.4/min. However, increasing concentration of acid (in a range of concentration investigated) did not give significant and constant change of adsorption rate constant. For step II process, adsorption involved physical interaction with the sufficient low adsorption energy (in a range of 311.3 - 1001 J/mol). Keywords: adsorption, cdmium, diatomaceous earth, kinetics.

ADSORPTION OF BACTERIOPHAGE UNDER VARIOUS PHYSIOLOGICAL CONDITIONS OF THE HOST

1. The adsorption rate constant of phage to bacterium is found to change between wide limits, depending on the physiological state of the bacterium. 2. The experiments of Krueger and of Schlesinger on the residual free phage in contact with an excess of bacteria are discussed and the view of Schlesinger, that they represent phage particles with reduced affinity to the bacterial host is supported by experiments. 3. The theory of von Smoluchowski and Schlesinger is compared with the experiments. 4. The implications of these findings for the assay methods currently used are discussed.